Grinding machine



NOV. 24, 1953 F, HEGEMAN 2,660,006

' GRINDING MACHINE Filed Feb. 25, 1950 4 sheets-sheet 1 H/S ATTORNEYNOV. 24, 1953 HEGEMAN 2,660,006

GRINDING MACHINE Filed Feb. 25, 1950 4 Sheets-Sheet 2 HA5 ATTORNEY NOV.24, 1953 HEGEMAN 2,660,006

GRINDING MACHINE Filed Feb. 25, 1950 4 Sheets-Sheet 3 INVENTORJ;

1 H/S Arrow/5x FIG. 6'

Nov. 24, 1953 F. P. HEGEMAN 2,660,005

GRINDING MACHINE Filed Feb. 25, 1950 4 Sheets-Sheet 4 uvvawroa; Fm mm 5Y H/S ATTOENEK Patented Nov. 24, 1953 GRINDING MACHINE Franklyn P.Hegeman, Union, N. J., assignor to General Motors Corporation, Detroit,Mich., a

corporation of Delaware Application February 25, 1950, Serial No.146,173

6 Claims.

This invention relates to grinding machines.

An object is to provide an improved machine for grinding the shoulder orflange at the larger end of the tapered raceway on the inner race ringof a tapered roller bearing. Another object is to grind a spherical zoneor face on the flange by an apparatus which will avoid chatter and otherdisadvantages, as by the use of a cupped grinding wheel which partiallyencloses the work, has an area of contact with the flange, and. isself-dressing. Usually such flanges have been ground conical by agrinding wheel outside of the race ring and having only line contactwith the flange. Another object is to provide improved mechanism forsupporting and feeding the grinding wheel into the work. To these endsand also to improve generally upon machines of this character, theinvention consists in the various matters hereinafter described andclaimed.

In the drawings,

Figs. 1A and 1B constitute chiefly a front e evation of the machine withsome parts in section.

Fig. 2 is a plan view of the wheel head and a portion of the work head.i

Fig. 3 is a plan view of the work head and a portion of the wheel head,a cam and its mounting being shown out of position in a cut-away portionof the work head.

Fig. 4 is a cross section of a slide and its adjusting means.

Fig. 5 is a left hand end view of the wheel head with the work headsupporting plates in section on the line 5-5 of Fig. 1B.

Fig. 6 is a left hand end view of the work head.

Fig. 7 is a diagram.

' Fig. 8 is a right hand end view of the wheel .head with parts omitted.

Fig. 9 is an exploded view of a feed cam and associated parts.

In the diagram, Fig. '7, W indicates an inner race ring having a taperedraceway R and a laterally projecting or outstanding flange F whoseinside face S is desirably ground to conform to a spherical surfacehaving its center C in the axis of the bearing. A relief groove isformed where the raceway and flan e would otherwise intersect. The faceof the flange between the relief groove and a rounded exterior corner isground by a cupped grinding wheel G whose axis intersects the point Cand lies at an an le to the axis of the race ring. The edge E or frontoperative grinding face of the wheel is a convex sp rical and sel dressn'due to it ar of contact with the flange. This area A is narrow but longcircumferentially forming a grinding zone indicated by the shaded areaand, as the race ring revolves, the whole face of the flange is engagedby the wheel. The long area of contact avoids chatter. The concavespherical face S will conform to the spherical ends of the taperedrollers used in the complete bearing and give them good guidance. Norun-in is required.

Referring to assembly Figure 1B, the grinding wheel G is attached'byscrews to an adapter 2 secured by a socket-headed clamping screw 4 tothe tapered end 6 of a spindle driven by a motor in a head 8 attached bya clam to (Figs. 4 and 8) to a slide"! 2. This slide has dovetail waysl4 guided in ways ona carrier plate I 6 for longitudinal adjustment ofthe grinding wheel as to compensate for wheel wear. Adjustment iseffected by a hand wheel l8 on a shaft 20 journalled in bushings in thecarrier plate and having a miter gear 22 meshing with a like gear keyedto a lead screw 24 (Fig. 2) against a collar thereof. V

The lead screw 24 has a smooth portion journalled in a bushing 26carried by the carrier plate and interposed between a washer 28 and awasher 30. These washers and the bushing are held on the screw shaft bya split nut 32. A nut 34 is attached to the bottom of the slide l2 andengages the lead screw. A floating or second nut 35 is guided in theslide l2 by a tongue in a slot and this second nut is pressed away fromthe first by a coil spring 38 to avoid backlash. The relative positionsof the slide I2 and the carrier plate are indicated by a scale on thehand wheel l8 and by an overlying pointer 40 fastened to the top of'abracket 42 mounted on the carrier plate. The wheel shaft passes throughthe bracket.

Feeding movement of the wheel axially to grind is effected by moving thecarrier plate IS a short distance while it is supported by parallel reedsprings which avoid wear. A reed spring 44 is attached to each end ofthe carrier plate by a clamping bar 46 secured by socket headed screws.The reed springs are similarly secured to a plate 48 mounted in anangled position (Fig. 2) on a base plate 50. The plate 48 is located onbase plate 50 by a pair of posts pressed into the base plate and havingrounded heads fitting holes in the plate 48, one of these posts beingillustrated at 52.

clamp the plates together. To flex the reed springs and s0 feed thegrinding wheel, a lever and cam mechanism is provided. A cam block- Setscrews twd'of which are shown at 54 level and support the plate 48 andother screws- 56 is fastened to the bottom of the carrier plate It andis engaged by the circular periphery of a cam 58 having a recess forreceiving the hub 60 of an actuating lever 62. The cam has a centralhole which is eccentric with respect to its periphery so that, when itis turned around a pivot post 64, it will exert forward thrust on thecam block 55. The pivot post has a bottom flange held down by a flangedclamping disc 86 fastened in a recess to the plate 48. The post has acentral recess for a member 68 havin an overhanging flange entering arecess in the hub of the lever. A screw H3 holds the member 68 to thepost but the lever and cam are allowed to turn freely as a unit around.the post.

Forward motion of the carrier plate is resisted by a bumper when one ofthe clamping bars 48 engages the bumper. The bumper comprises a screw I2adjustably secured in an inner sleeve I4 by nuts threaded on the ends.Rubber like material I6 is bonded to the sleeve and 'to an outer sleeve18 clamped by a plate 80 in a bumper block 3| which is fastened to thebase plate 50. The base plate is rigidly secured to a main frame whichmay be the frame of a Van Norman oscillating grinder of the typeillustrated in the U. .S. patent to Van Norman No. 1,722,691 and whoseoscillating column is used only to swine the work head into and out ofthe grinding position.

The work ring W (Fig. 1A) is clamped in the axis of a suitable chuck aainst an abutment flange by moving an internally tapered sleeve 82inwardly along an externally tapered nose 84. The sleeve is slit in fromeach end to make it expansible against the Work and is engaged by theheaded end section '86 of a sectional draw bar 88. The chuck is securedby angularly arranged set screws 90 to an adapter 92 secured to thespindle head by screws, the spindle being suitably journalled in a workhead 94 and having a belt driven pulley 96 secured thereon. A coilspring 98 is interposed between the pulley and a collar I III) clampedon the draw bar. A ball thrust bearing I02 engages the collar and arounded surface I04 on a lever I06 pivoted to a plate I08 fastened onthe top of the work head. The lever comprises two companion pairs ofangularly related arms rigidly connected by a series of spacing blockswelded between them, the vertical lower end of the lever carrying a camroller I I which is rotatably secured by a headed stud. The lever isguided between two spaced arms II 2 on a bracket attached to the workhead. A coil spring II4 is connected to the lever and to an anchor poston the work head to hold the arm against the thrust bearing. The drawbar spring-98 is the stronger of the two springs and urges the rollerIIIl towards a cam II6 which is secured by a screw to a slide II8 whichis adjustably' secured on the horizontal leg of an angle bracket I fixedto the main frame. The slide has a tongue entering a groove in thebracket and its adjusted position is secured by a, screw I22. In theworking position, the cam roll is remote from the cam but, as willappear, the work head and its mounting can be swung around an axis tofacilitate the removal of the work from the chuck which projects intothe grinding wheel. Upon this swinging movement around a center point P(Fig. 3) the cam roller engages the cam and releases the work. Fig. 3shows the cam roller in broken lines against the cam.

The work head 94 is adjustable axially by a screw I24 on an upper slideI26 and that slide is adjustable crosswise by a screw .28 On a lower 4guide plate I30 which is fastened by screws to a swivel plate I34. Theswivel plate is angularly adjustable on a base plate I36 and, for thispurpose, a pivot plug I38 having a collar at the bottom extends upthrough the base plate into an opening in the swivel plate to receive a,securing bolt I40 threaded into the plug with the head of the boltengaging a washer. A pin holds the washer from rotation and a pin holdsthe plug from rotation. The swivel plate is locked in angularlyadjustable position by a series of three threaded studs I42 which arethreaded in the base plate I35 and pass up through three arcuate :slotsI44 in the swivel plate to receive clamping nuts and washers. The slotsare curved about a center at the pivot plug I38 and this is not the samecenter as the point P. It will be seen that the swivel plate locates thework spindle axis at a selected angle to the axis of the grinding wheelber I48 which is secured to the oscillating column of a Van Normanoscillating grinder, of the type illustrated in the U. S. patent to VanNorman No. 1,722,691, and oscillates in that machine around a center atthe point P. In that machine this member has a dovetail way I50 for aslide but in the present instance that slideway is not used and the baseplate I36 is rigidly secured to the member I48 by screws. In the presentmachine, instead of constant oscillation, there is only one swingingmovement of each work piece. This swinging movement to load and unloadthe chuck may be accomplished in any suitable way, as by a piston andcylinder unit (not shown) attached to the main frame and having thepiston rod engaging a, slot in a disc on the oscillating column. Theswinging movement around the center P is limited definitely towardsoperative position by stop buttons carried in a depending projection I52on the oscillatable column, the buttons engaging a stop screw I54 in afixed stop block I56 in one direction and in the other direction by astop screw I58 in a block I60, both blocks being secured to the frame.The swivelling center of the swivel plate I34, that is, the pivot plugI38 is located in a vertical line at the grinding edge of the grindingwheel and at the relief groove where the tapered raceway R and thespherical face S would otherwise intersect.

The grinding wheel requires a certain thickness for strength but a thickedge would wear near the interior and the exterior portion wouldultimately project over the work flange F. To prevent the interferenceof the wheel with the outer corner of the flange due to such wear, thewheel is occasionally dressed off in an are at its outer edge. For thispurpose a diamond I62 is mounted below the lower edge of the wheel foroscillation with a rock shaft I64 having a hand wheel I66. The diamondis mounted on a plug 338 secured by a set screw in a hole in the rockshaft, whose axis lies in a plane including the axis of the pivot plugI38. The rock shaft is journalled near the front end in a roller bearing110 in a bracket I12 mounted on the base plate I36. The shaft is alsojournalled in two sets of roller bearings I'M separated by a spacer in abore at theoverhanging portion of a rear bracket I16. Washers hold theneedle rollers in the front bracket and collars hold the needle rollersin the boreof the rear bracket.

In setting up the machine for a particular run of work, a work piece isplaced in the chuck and the work head is swung into operative positionaround the center point P. The intersection of the flange F and theraceway R is then lined up vertically with the center of the pivot plugI38 by proper longitudinal and crosswise adjustment of the two work headslides. The correct radius of the spherical face S is produced byswivelling the swivel plate 1313 around the pivot plug I38 until thework axis intersects the wheel axisat the desired distance from theflange. The swivel plate is then secured by its screws. Before grindingbegins, the bumper E6 is under a preload which holds the grinding wheelout of contact with the work. The wheel is advanced into the work bymanipulation of the handle to an extent determined by the operator. Whenthe cam handle is swung back, the preloaded bumper moves the wheel away.The work head is then swung around the center pivot P. During thisswinging the cam roller H engages the fixed cam H6 and the draw bar isthereby operated to release the work from the chuck.

I claim:

1. In a machine for grinding a spherical surface on a flange upstandingfrom the tapered raceway of a bearing ring, a work head having a worksupport journalled about an axis, a cupshaped grinding wheel journalledabout an axis intersecting the work support axis, the grinding wheelhaving a cylindrical wall terminating in a parti-spherical end grindingface to surround the work support and engage the spherical surface ofthe flange, the center of curvature of said parti-spherical grindingface lying at the intersection of said axes, a swivel plate supportingthe work head and having a pivot provided with an axis tangent to saidend grinding face, a rock shaft mounted on the swivel plate with itsaxis in a plane through the pivot axis, and a tool mounted on the rockshaft to cut down the thickness of the outer portion of the wheel beyondthe spherical edge.

2. In a machine for grinding a side face on a flange upstanding from theraceway of a bearing ring, a rotatable work head arranged to support thebearing ring, a rotatable wheel head, a grinding wheel mounted on thewheel head and adapted to engage the flange, a carrier plate, a slidemounted on the carrier plate and supporting the wheel head for movementtowards the work to compensate for wheel wear, a supporting plate belowthe carrier plate, parallel springs connecting the plates, a preloadedresiliently yieldable bumper resisting movement of the carrier plate,and a cam mounted on the supporting plate and operatively related to thecarrier plate for shifting the carrier plate in opposition to theyieldable bumper.

3. In a machine for grinding a spherical surface on an annular flangeoutstanding from the tapered raceway of a bearing ring, a work headrotatably driven about an axis and having a chuck arranged todemountably hold the bearing ring, a rotatably driven wheel headjournalled about an axis, said axes intersecting in predeterminedangular relation, a cup-shaped grinding Wheel on the wheel head andhaving a' cylin'-' drical wall terminating in a spherical end grindingface engageable with the spherical surface on the flange, the centerabout which the spherical grinding wheel face is formed lying at theintersection of the axes during grinding, the grinding wheel enclosinga, portion of the chuck during grinding, a swinging support carrying thework head to remove the grinding wheel from said enclosing relation, andcam mechanism operatively connected to release the chuck fromholdingrelation with the bearing ring, said cam mechanism being responsive tothe swinging of the support.

4. In a machine for grinding a spherical surface on a flange laterallyprojecting from the tapered raceway of a bearing ring, a cup-shapedgrinding wheel having a cylindrical wall terminating in an annularspherical grinding face engageable with the spherical surface of theflange, a rotatable work head having a chuck for supporting the ring forrotation, a rotatable wheel head supporting the grinding wheel forrotation, the axis of the work head and the axis of the wheel headintersecting one another on the center of the spherical curvature of theoperative grinding wheel face when the grinding wheel is in grindingposition, said grinding wheel enclosing a portion of the chuck, aswinging support carrying the work head, a slidable drawbar operativelyconnected to the chuck, a lever operatively connected to slide thedrawbar, an oscillatable member operatively connected to the work headto swing the work head and said swinging support as a unit and carry thechuck out of the grinding wheel, and a cam in the path of the levercausing the chuck to release the bearing ring during the swingingmovement of the support.

5. In a machine for grinding a curved surface on a flange upstandingfrom the tapered raceway of a bearing ring, a support rotatably drivenabout its axis, a, chuck on the support for demountably receiving thebearing ring, a cupped grinding wheel rotatably driven about its axisand enclosing the end of said chuck, the cupped grinding wheel having afront operative grinding face spherically curved about a centerrearwardly of said face and in the axis of said support, thecircumferential wall of the grinding wheel being radially thicker thanthe width of its operative grinding face, dressing mechanism adjacentthe forward end of the grinding wheel and engageable with the wheelperiphery to cut back said front grinding face to a width approximatelyequal to the radial width of said upstanding flange.

6. In a machine for grinding a spherical surface on a flange upstandingfrom the tapered raceway of a bearing ring, a rotatable work head and arotatable grinding wheel support having their axes intersecting outsideof the work head, a chuck on the work head for demountably holding thebearing ring, a cup shaped grinding wheel having an annular end grindingface engageable with said flange, all parts of the end grinding facebeing equidistant from the intersection of said axes, a pair of slidesand a swivel plate supporting the work head, the swivel plate having apivot provided with an axis, feeding mechanism adjustably positioningone slide axially of the work head, feeding mechanism adjustablypositioning the other slide crosswise of the work head, said feedingmechanisms locating the work head with the axis of the pivot tangent ithgm gr nd n face at the rin n Wheel during gr 1: 1-1 2, and adiustable'mechan sm positionia the swiv l p ate i a sel eted location mund the v te mg rad us. of mg spherical suxfw medu ed: by the rin in Wh e FRANKLYNHEGEMAN.

Referencs Cited in the file of this patent UNITED STATES PATENTS NumberName Date Re 13,892 Van Norman Mar. 1 6 19.1 5 1,401,831 Taylor Dec. 271921 1,617,167 Schramm Feb. 8, 1927 1,994,529 Meyer Mar. 19, 1935 Numban1 Number Q2155. Qmnberg mam-1. J k 2 .32 N nnmg x? "7.1211220- 3 35 Ann13.. L937. Mar- 11 19.32

walkr Dec. 7, 1943 Carlson 22-2-1922. June 1 1 FOREIGN PATENTS cguntryDan: Sweden. 2 --r Jan V 6 S p -1 1811 r-.-,- Jan- 2 1938'

